D-AOC PCBs - the building and help Thread

tzman

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Dec 7, 2009
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zayance said:
Finally had time to finish the late Christmas present i made myself, wanted to make it look fancy for my first Tube project, i think that's mission acomplished, but don't know if i'll do on my next build tough  ::). Had some tiny issues but all is good.
I got to thank Volker and Analag for the project, Franck @NRG for all the panel work Danke Schoën to you guys i'll have an Augustiner on this one, PROST!
Also like to thank Mad.Ax for his help and clarifications (merci monsieur) and all of you guys here for the inspiration and help also, without the forum i wouldn't even have tought about all this.

On quick sound check, i was pleased by the sound and compression, i'll use it as is for some time and tweak on taste, i just have a low HT when all tubes are in 188V at R128  ???, but all works as expected, all matched as possible etc....

Nice!

I see you're using SCR Audio caps, right?
What value did you use for Cx04? And what exactly did you use for the curve mod? Blue LED's, double vactrol?

Cheers!
 

Holger

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Wow. Fresh design, heatsink overkill, switched resistors rather than pots, really nice.
What capacitors are you using instead Wimas?
How did you built the hard/soft curve adjustment?
Regarding the meter zero pots: have you ever used them once the right value was found, IOW does your zero GR point move?
 

zayance

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Thanks guys.

I see you're using SCR Audio caps, right?
What value did you use for Cx04? And what exactly did you use for the curve mod? Blue LED's, double vactrol?

Yes SCR, why SCR? well just to add a little french in there  :D, and i went stock values meaning 100nF for Cx04

How did you built the hard/soft curve adjustment?

I made myself a litte PCB based on a 2*6 Lorlin, saves some wiring, i went for 5 curves, but i guess 3 or 4 would have been enough.
Simple Vactrol for now, and i soldered Blue//; Red //; 1K; 100K; Blue anti//, red doesn't do much, i'll try some other things, but i'm still tweaking and  learning here so....
EDIT: I went for Blue//; 1K ; 100K ; Blue anti// ; Red anti//, that is what it seems to be for now, going from Soft to Hard.

Regarding the meter zero pots: have you ever used them once the right value was found, IOW does your zero GR point move?

Doesn't move much, but it did, maybe not something very important on this one, your idea of a trimmer would have been good also, will see with time, it's freshly made so i need to use a lot and see how it behaves, overall pros and cons, what can be changed or not need to  etc.....
But on quick sound check i liked a lot what i heard, and i'm not saying this because i have to  :p :D, i was pretty confident about the overall result, i trust people around here more then the people out there (i mean in the industry) haha

heatsink overkill

Actually it was for TO220 Package of the lm350, but after some time i was doing an order on Mouser and found an lm350K on TO3 for a descent price, so after seeing this heatsink, i said hoooooo my precious  :D, installed another one  :p, all gets warm not hot, but safe.....
 

[silent:arts]

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zayance said:
Danke Schoën to you guys i'll have an Augustiner on this one, PROST!

Enjoy! (Augustiner and D-AOC)!
Very nice built, and a fantastic looking unique front panel  :) :) :)

DAOC-zayance.gif
 

Peter A

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Feb 8, 2005
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Svendborg, Denmark
Hallo dear d-aoc fellows.

I'm about to finish my d-aoc and have some questions.

Last night I swaped my input iron, edcor 1:1 with JLM14 1:4 to get more action on the input.
I now get a lot of distortion, especialy in the low freq. and have to back down on the output on my preamp.  Is that to be expected?

When the unit is compressing heavely, It seems to lose some high freq. Is that normal?

I have done no mods except for the input iron. I'm planning to try some of Kubis mods shortly.

I'm not sure, but i think that the edcors roll of a bit highs (very subtle) compared to the jlm14. I have not measured it yet, just my immidiate impression.
Any way the unit sounds very well and performes well as a tracking comp. (have only tried it on akustik guitar so far)
I'l post some picks and other details later on, when the unit is finished.

Best regards

Peter
 

Peter A

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Feb 8, 2005
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Svendborg, Denmark
Hallo

Well finally finished my tube comp.
Got this Purusha case and pcbs lieing around for a couple of years and finally got it done.

d-aoc_front01.jpg


d-aoc_detail_vactrol01.jpg


More pics here:

http://twin-x.com/groupdiy/displayimage.php?album=random&cat=11161&pos=-4424



I'm very pleased with the sound and behaviour og this machine. I look forward to using it.

I have installed double vactrols, which I ordert matched from the Banzai shop.
I have 2 slopes. One with double (hard) and another with 330r across a single vactrol (soft).

I did not like the JLM input transformers because of the low freq distortion. To much input I guess. I will have to use them for another job. 
The Edcor 10K 10K are doing a great job so I think they are keepers.

I have a 470R 50w resistor between board and power transformer giving me 245V. The Music Ding trafo gave 280V without resistor. A bit on the hi side I thought.
Meters are from Hair Ball with led lighting. They look nice and I have pretty precise meter readings. (with a 50k trimmer in place of  x26)

Only problem for now is the stereo tracking with the link switch engaged. It is 2 or 3 db off on one side.
I’m also a bit concerned about the heat from the regulators. I can touch them without getting burned but they are HOT.


Very special Thanks to Analag, Silent Arts and Kubi for this fine projekt. Also a big thanks to everybody  in this great forum! This place is fantastic :)

Best regards Peter
 

[silent:arts]

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Hi Peter,

nice and clean build, congratulation!

the JLM input transformers are Mic input transformers,
my guess is with normal studio levels distortion is to be expected.

DAOC-PeterA.gif
 

Script

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What tubes is everyone using?

I know, I know... one and the same tube sounds different depending on the circuit, and different people use different tubes depending on the sound they prefer...

What do I prefer? Well, clarity, I guess. I opted for building the DOAC because I read that it's rather on the transparent side. So naturally I wonder whether different tubes (from standard JJ to esoteric) make much of a difference here. I have JJs (12AU7) and EHs (12AT7) lying around from another project, but thought maybe it's time to try something different. However, I don't intent to invest money on Telefunken etc. -- but there are many bottles from various makers inbetween. Anyway, I'd have to order them first, and using different tubes in the DAOC is a topic that seems little discussed. Is there a reason?

Anyone willing to share experiences with testing different tubes in this comp? Any observation would be much appreciated.

Cheers
 

dagoose

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Script said:
What tubes is everyone using?

I know, I know... one and the same tube sounds different depending on the circuit, and different people use different tubes depending on the sound they prefer...

What do I prefer? Well, clarity, I guess. I opted for building the DOAC because I read that it's rather on the transparent side. So naturally I wonder whether different tubes (from standard JJ to esoteric) make much of a difference here. I have JJs (12AU7) and EHs (12AT7) lying around from another project, but thought maybe it's time to try something different. However, I don't intent to invest money on Telefunken etc. -- but there are many bottles from various makers inbetween. Anyway, I'd have to order them first, and using different tubes in the DAOC is a topic that seems little discussed. Is there a reason?

Anyone willing to share experiences with testing different tubes in this comp? Any observation would be much appreciated.

Cheers

Good question.. i'm also thinking about getting better tubes for this things since i use it quite a lot for mastering. Love it for that!
Mullard tubes seem to be really good but are also really expensive and so i'm not sure if it's worth the money. So any good alterneatives? I think i have JJ's as well, not sure, have to open it up. I didn't spend to much on the tubes back then.
 

Script

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R 25 (470K) is for negative feedback in amp stage, trading unused gain for higher linearity?
 

dagoose

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radiance said:
Would a transformer upgrade not make more of a difference instead of tube's? Maybe Holger can shed a light on this...??
It does indeed, mine has lundahls ((the ones i bought from you way back) which was a big step up to the edcors!
 

radiance

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dagoose said:
radiance said:
Would a transformer upgrade not make more of a difference instead of tube's? Maybe Holger can shed a light on this...??
It does indeed, mine has lundahls ((the ones i bought from you way back) which was a big step up to the edcors!

ow...now you mention it ....LOL  :p
 

Holger

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radiance said:
Would a transformer upgrade not make more of a difference instead of tube's? Maybe Holger can shed a light on this...??

See it this way: you see the 20$ Edcors, and you see the wonderful painted 25£ Carnhills. What can your ears tell you when you already know this?  ;)
Never tried a direct comparison, I hope that I'll have time some days.
So, IIRC, there is a slight but noticeable improvement. BTW; I'm still using the cheapo JJ tubes. Never changed them and I'm certainly not willing to spend the next projects money on tube exchanges.
If my mixes are noisy, I use Adobe Audition's noise removal tools to get rid of the dirt, if there's any.
 

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